Average U.S. rates on fixed mortgages declined slightly this week as the spring home-buying season has gotten off to a slow start.

Mortgage buyer Freddie Mac said Thursday the average rate for the 30-year loan eased to 4.29 percent from 4.33 percent last week. The average for the 15-year mortgage ticked down to 3.38 percent from 3.39 percent.

Mortgage rates have risen almost a full percentage point since hitting record lows about a year ago.

Warmer weather has yet to boost home-buying as it normally does. Rising prices and higher rates have made affordability a problem for would-be buyers, while many homeowners are reluctant to list their properties for sale. Roughly a third of homeowners owe more on their mortgage than they could recoup from a sale.

Data released Tuesday showed U.S. home-price gains slowed in February from a year earlier for the third straight month, as harsh winter weather and high prices have slowed sales. According to the Standard & Poor’s/Case-Shiller 20-city home price index, home prices fell in 13 of the 20 cities in February compared with January.

Average prices nationally are expected to rise by single digits this year, after a double-digit surge last year as home values rebounded from the Great Recession.

The increase in mortgage rates over the year was driven by speculation that the Federal Reserve would reduce its $85 billion-a-month bond purchases, which have helped keep long-term interest rates low. Indeed, the Fed has announced four $10 billion declines in its monthly bond purchases since December.

The latest came this week as Fed officials decided to reduce the monthly purchases to $45 billion a month, because they believe the economy is steadily healing. However, the central bank expects its benchmark short-term rate to remain unusually low.

To calculate average mortgage rates, Freddie Mac surveys lenders across the country between Monday and Wednesday each week. The average doesn’t include extra fees, known as points, which most borrowers must pay to get the lowest rates. One point equals 1 percent of the loan amount.

The average fee for a 30-year mortgage rose to 0.7 point from 0.6 point a week ago. The fee for a 15-year loan remained at 0.6 point.

The average rate on a one-year adjustable-rate mortgage edged up to 2.45 percent from 2.44 percent. The average fee held steady at 0.5 point.

The average rate on a five-year adjustable mortgage increased to 3.05 percent from 3.03 percent. The fee declined to 0.4 point from 0.5 point.